Co-location wins latency, and density wins co-location. The closer the normalization cores sit to the ingest NICs, the fewer microseconds a tick spends in transit — so we pack the stack tight. The price of that proximity is heat, and heat is a freshness problem wearing a hardware costume.
When a dense stack runs hot, the firmware throttles. Throttling does not crash anything; it just quietly stretches every per-event deadline. In a naive system that is invisible until a desk complains. In LIAW it surfaces immediately, because the provenance stamp records observed processing time, and a thermal slowdown shows up as a measurable drift in per-source freshness.
So the cooling policy is written against the latency budget, not against a temperature alarm. We cap sustained clock before we approach the thermal ceiling, trading a sliver of peak throughput for a flat freshness curve. A predictable slow core beats an occasionally-fast one when consumers are paying for determinism.
STACK CORES SUSTAINED_GHZ THERMAL_HEADROOM FRESHNESS_P99 rack-a1 64 3.4 18 C 0.05 ms rack-a2 64 3.4 21 C 0.05 ms rack-b1 48 3.6 14 C 0.06 ms
The result is boring on purpose: a freshness curve you can plot as a flat line, because the thermal envelope was budgeted before the first core was ever racked.